#define _CRT_SECURE_NO_WARNINGS 1
#include<stdio.h>
#define MAXN 10
typedef float ElementType;

struct heap
{
    int* a;
    int size;
    int capacity;
}hp;

ElementType Median(ElementType A[], int N);

int main()
{
    ElementType A[MAXN];
    int N, i;

    scanf("%d", &N);
    for (i = 0; i < N; i++)
        scanf("%f", &A[i]);
    printf("%.2f\n", Median(A, N));

    return 0;
}



void Swap(int* p1, int* p2)
{
    int tmp = *p1;
    *p1 = *p2;
    *p2 = tmp;
}


void Adjustdown(int* a, int n, int parent)
{
    int child = parent * 2 + 1;
    while (child < n)
    {
        if (child + 1<n && a[child + 1] > a[child])
            child++;
        if (a[child] > a[parent])
        {
            Swap(&a[child], &a[parent]);
            parent = child;
            child = parent * 2 + 1;
        }
        else break;
    }
}

heapsort(int* a, int n)
{
    for (int i = (n - 1 - 1) / 2; i >= 0; i--)
    {
        Adjustdown(a, n, i);
    }
    int end = n - 1;
    while (end > 0)
    {
        Swap(&a[0], &a[end]);
        Adjustdown(a, end, 0);
        end--;
    }
}



ElementType Median(ElementType A[], int N) {
    heapsort(A, N);
    return A[N / 2];
}